In the related art, a head-up display device (hereinafter, referred to as a “HUD device”) is known as a device which practically displays a virtual image of a display image by causing a screen member to diffuse a laser beam configuring the display image and to guide the laser beam toward a projection surface.
For example, a HUD device disclosed in Patent Literature 1 causes multiple optical elements in a latticed array to diffuse a laser beam which is projected from a projector and which is incident on a screen member. The laser beam which is diffused and projected on a projection surface in this way is viewed as a virtual image of a display image by a viewer located inside an interior of a moving body.